According to the pics from last month she is clearly over the three months.
It will be their first child and the pregnancy is viewable.
The message she wrote was clearly not meant for others than her husband

Apparently, Archduchess Gabriella's Facebook page has or had a picture of her and a visibly and obviously pregnant Archduchess Marie Christine, taken at the beach.

If the picture hasn't been taken down that's a pretty clear indication that it was posted "with approval". There are ways and means of getting news out to those who are interested without the need for press releases or official announcements.

__________________
I had a dream: Let's connect our thoughts together, than we have a mission, let's connect our feelings together, than we have a mood, let's connect our dreams together, than we have a vision and let's connect our mission, our mood and our vision together than we have a perfect life.

According to Hein at Nobiliana (Births Non Gotha 2013), Marie-Christine and Rodolphe have now a second son, Constantin, born 25-10-2013.

__________________
I had a dream: Let's connect our thoughts together, than we have a mission, let's connect our feelings together, than we have a mood, let's connect our dreams together, than we have a vision and let's connect our mission, our mood and our vision together than we have a perfect life.